The present invention relates to a developing device and an image forming apparatus.
In general, a conventional image forming apparatus of an electro-photography type includes a conventional developing device. The conventional developing device includes a photosensitive member as an image supporting member; a charging roller for uniformly charging a surface of the photosensitive drum; a developing roller as a developer supporting member for attaching toner as developer to a static latent image formed on the surface of the photosensitive drum to develop the static latent image; a supply roller as a developer supplying member for supplying toner to the developing roller; a developing blade as a developer layer regulating member for regulating a toner layer thickness on a surface of the developing roller; and the like.
In the conventional developing device of the conventional image forming apparatus, the developing roller is provided for attaching toner as developer to the static latent image formed on the surface of the photosensitive drum to develop the static latent image. The developing roller may include a surface layer (refer to Patent Reference).    Patent Reference: Japanese Patent Publication No. 2010-152024
According to Patent Reference, in the conventional developing device of the conventional image forming apparatus with the configuration described above, toner particles and an outer additive separated from the toner particles may be attached or fixed to the surface of the developing roller, thereby causing a phenomenon called toner filming. When the toner filming occurs, it is difficult to perform a printing operation with high quality.
In view of the problems described above, an object of the present invention is to provide a developing device and an image forming apparatus capable of solving the problems of the conventional developing device. In the present invention, it is possible to prevent toner particles and an outer additive separated from the toner particles from being attached or fixed to a surface of a developing roller, thereby preventing the toner filming.
Further objects and advantages of the invention will be apparent from the following description of the invention.